© Semiconductor Components Industries, LLC, 2011
November, 2011 − Rev. 3
1 Publication Order Number:
CAT4137/D
CAT4137
CMOS Boost Converter -
White LED Driver
Description
The CAT4137 is a DC/DC step-up converter that delivers a
regulated output current. Operation at a constant switching frequency
of 1 MHz allows the device to be used with small value external
ceramic capacitors and inductor.
The device drives a string of white LEDs connected in series and
provides the regulated current to control the LEDs with inherent
uniform brightness and matching. An external resistor R1 sets the
output current and allows up to 30 mA current to be supported over a
wide range of input supply voltages from 2.2 V to 5.5 V, making the
device ideal for battery-powered applications.
LED dimming can be done by using a DC voltage, a logic signal, or
a pulse width modulation (PWM) signal. The shutdown control pin
allows the device to be placed in power-down mode with “zero”
quiescent current.
In addition to thermal protection and overload current limiting, the
device also enters a very low power operating mode during “Open
LED” fault conditions. The device is housed in a low profile (1 mm
max height) 5−lead thin SOT23 package for space critical
applications.
Features
• Drives up to 5 White LEDs from 3 V
• Power Efficiency up to 87%
• Low Quiescent Ground Current 0.1 mA
• Adjustable Output Current (up to 30 mA)
• High Frequency 1 MHz Operation
• “Zero” Current Shutdown Mode
• Operates Down to 2 V (from Two AA Batteries)
• Soft Start Power-up
• Open LED Low Power Mode
• Automatic Shutdown at 1.9 V (UVLO)
• Thermal Shutdown Protection
• Thin SOT23 5−lead (1 mm Max Height)
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Applications
• LCD Backlighting
• Cellular Phones
• Handheld Devices
• Digital Cameras
http://onsemi.com
TSOT−23
TD SUFFIX
CASE 419AE
PIN CONNECTIONS
UEYM
MARKING DIAGRAMS
Device Package Shipping (Note 4)
ORDERING INFORMATION (Note 3)
CAT4137TD−T3
(Note 1)
TSOT−23
(Pb−Free)
3,000/
Tape & Reel
LX = CAT4137TD−T3
UE = CAT4137TD−GT3
Y = Production Year (Last Digit)
M = Production Month (1−9, A, B, C)
1
5
(Top View)
VIN
SHDN
SW
GND
FB
1
LXYM
CAT4137TD−GT3
(Note 2)
TSOT−23
(Pb−Free)
3,000/
Tape & Reel
1. Matte−Tin Plated Finish (RoHS−compliant).
2. NiPdAu Plated Finish (RoHS−compliant)
3. For detailed information and a breakdown of
device nomenclature and numbering systems,
please see the ON Semiconductor Device No-
menclature document, TND310/D, available at
www.onsemi.com
4. For information on tape and reel specifications, in-
cluding part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifica-
tions Brochure, BRD8011/D.
